The present invention relates to stabilization of food products against rancidity and moisture spoilage, and more particularly to an article and method for inhibitinig oxidation and for reducing the moisture content of packaged products prone to such spoilage.
Low moisture products are typically packaged and stored in containers in which air is present. Oxygen present within the product itself or in the surrounding air can contribute, in varying degrees, to the degradation of the stored product. Of these products, foods containing a significant proportion of oils high in poly- or mono-unsaturated fatty acids are particularly subject to spoilage, since the multiple double bonds present in such oils are readily oxidized. The rate of oxidation is even greater for oils in the refined state and for foods lacking a coat providing a partial protective barrier, for example nuts removed from the shells and subsequently stored.
The use of antioxidants to preserve foods is known in the art and embraces many suitable compounds capable of slowing the normally occurring rate of oxidation. Used as a food additive incorporated directly in the product or applied to the exterior thereof where homogeneous inclusion is not possible, such compounds slow the natural rate of oxidation of the food product.
Among such antioxidants, ethoxyquin, for example, has been widely used in prolonging shelf-life of various consumable materials, particularly those stored in bulk. Examples of such consumables include materials with a potentially high degree of rancidity such as pecans, peanuts, walnuts, macadamias, pignoli nuts, as well as other items, including dry or prepared cereals and breakfast products, unrefined natural grains, seeds, many health foods, pharmaceuticals, vitamins, dried fruit packages, etc. Although effective as an antioxidant, its use, however, is subject to a variety of drawbacks. In its pure state, under normal ambient conditions, ethoxyquin (6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline) is a viscous-like oil having a viscosity of approximately 300 cps, for example, at 20.degree. C. This high viscosity makes the even distribution throughout the food product, in typically applied concentrations below 150 ppm, exceedingly difficult, thus introducing the tendency of localized pockets of higher, undesirable concentrations. In addition, ethoxyquin is relatively insoluble in water, rendering its introduction as an aqueous solution impracticable. Suppliers generally recommend that ethoxyquin be premixed with a suitable carrier, such as an oil diluent, prior to spraying on foodstuffs. Alternatively, it has been suggested in the art that the ethoxyquin might be homogeneously distributed effectively throughout the food product by creating an emulsifier-stabilized suspension or by impregnating powderized silica gel with the ethoxyquin, and applying the resultant modified form of antioxidant. However, even when usable to a satisfactory degree in such forms, ethoxyquin remains susceptible to degradation caused by exposure to oxygen, particularly in the presence of light and elevated temperatures. Thus, maintaining continued viability prior to use may make its prolonged storage difficult.
In addition to ethoxyquin, other antioxidants currently available include, for example, ascorbyl palmitate, stearate or oleate, propyl gallate and other gallate esters, BHA (butylated hydroxy anisole), BHT (butylated hydroxy toluene), tocopherols and salts thereof (either natural or synthetic), TBHQ (tertiary butyl hydro quinone), etc., which like ethoxyquin, are fat soluble. Blends of the above listed antioxidants may also be used in combination. Although approved as food additives by the Food and Drug Administration (FDA), there has been an ever increasing public concern regarding introduction of artificial additives, such as the above listed antioxidants as well as ethoxyquin, directly into food. Notwithstanding these health concerns, substantiated or otherwise, limiting the amount of antioxidants applied to the consumable product is important from the standpoint of palatability, since such additives can adversely affect taste and possibly impart an undesirable odor to the food material, particularly as their concentration is increased.
An alternative approach taken in the prior art for reducing oxidation and inhibiting development of rancidity in susceptible foodstuffs, involves the use of oxygen-absorbing compositions which, when included in a sealed container, reduce the product's exposure to oxygen by depleting, consuming, or otherwise reducing the free oxygen contained therein. These so called "oxygen scavengers" are either included as a formed layer, or layers, affixed to the interior of the container, or are packaged in an enclosed vapor-permeable bag or packet which may then be included along with the stored product. Unlike the above described antioxidants which are applied directly to the food, discrete packaging of the oxygen absorbents provides the advantage of preventing direct contact of the compositions with the food products. Several drawbacks, however, relate to the use of these oxygen absorbents. Because of the strong affinity of such compounds for atmospheric oxygen, storage and handling of oxygen absorbents can present problems. In addition, such compositions are generally limited to use with products stored in airtight containers which are not repeatedly opened and resealed, since replenishment of atmospheric oxygen would rapidly deplete the oxygen absorptive properties of the composition.
Accordingly, it is an object of the invention to provide an antioxidant composition in a form, and a method for use of same, which overcomes the drawbacks of the prior art.
It is a further object of the invention to provide an antioxidant composition which may be included within a containerized stored product in a manner which will enhance even distribution throughout the product without creating regions of excessive concentration, and which obviates the introduction of same as a sprayed liquid applied directly to the foodstuffs.
It is a still further object of the invention to provide such antioxidant composition in a form permitting reliable storage over extended periods prior to use without significant loss of chemical viability.
It is yet a further object of the invention to provide an antioxidant composition which reduces the moisture content of the stored product while simultaneously imparting resistance against product degradation, including loss of nutrients and pigmentation, and mold formation.
Still another further object of the invention is to provide an antioxidant composition in a form which is economically produced in an easily handled form which may be added to a storedproduct with a minimum of difficulty.